Spd浸种对盐胁迫下番茄(Solanum lycopersicum)幼苗的保护效应

Protective effects of pre-socked seeds with Spd on tomato seedlings under NaCl stress

通过水培试验,研究了100mmol/LNaCl盐浓度下,0.25mmol/LSpd浸种处理对两个番茄品种白果强丰(耐盐基因型)和江蔬14号(盐敏感基因型)植株干重、根冠比(R/T)、幼苗叶片和根系抗氧化酶活性及活性氧含量的影响。具体试验处理如下:(a)对照(蒸馏水浸种+0mmol/LNaCl),(b)NaCl(蒸馏水浸种+100mmol/LNaCl),(c)Spd(0.25mmol/LSpd浸种+100mmol/LNaCl)。结果表明,在盐胁迫下,两个番茄品种幼苗叶片和根系内超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性升高,H2O2含量和O2.-产生速率增高,幼苗生长受到抑制,幼苗地上部、地下部干重均明显低于对照,R/T增大,且江蔬14号的变化幅度大于白果强丰。Spd浸种处理降低了盐胁迫下番茄幼苗叶片和根系内O2.-产生速率和H2O2含量,进一步提高了SOD、POD和CAT活性,促进幼苗干重增加,缓解了盐胁迫对植株的伤害。与耐盐基因型番茄品种白果强丰相比,Spd浸种处理对盐敏感基因型番茄品种江蔬14号的作用效果更为明显。总之,Spd浸种处理通过提高盐胁迫下植株体内抗氧化酶活性,降低ROS水平来缓解盐胁迫对番茄幼苗的伤害,提高幼苗耐盐能力。

To evaluate the protective effects of exogenous spermidine （Spd） on tomato seedlings against salt stress, antioxidant enzymes activities in roots and leaves, dry weight of seedlings, and the ratio of root to shoot （R/T） were assayed in two tomato cuhivars（ Cucumis sativus cv. Baiguoqiangeng and cv. Jiangshu NO. 14） with different resistances to salt stress after their seeds were pre-socked with Spd and their seedlings were treated with NaCl. Three experimental treatments from different concentrations of Spd and NaCl were used, （a） dd H2O ＋ 0 mmol/L NaCl, as the control, （b） dd H2O ＋ 100 mmol/L NaCl, and （c） 0.25 mmol/L Spd ＋ 100 mmol/L NaC1. The results showed the activities of three antioxidant enzymes of superoxide dismutase （SOD）, peroxidase （POD） and catalase （CAT）, production rate of superoxide anion （ O2^.- ） , and content of hydrogen peroxide （ H2 O2 ） in leaves and roots of tomato seedlings all increased under the salt stress. Dry weight of tomato seedlings reduced significantly, while the ratio of root to shoot（R/T） increased in both cuhivars. The treatments of pre-socked seeds with Spd can increase antioxidant enzymes of SOD, POD, and CAT, and decrease contents of O2^.- and H2O2 in the seedlings. Pre-socked seeds with Spd had better effects to the salt sensitive cultivar ‘ Jiangshu NO. 14＇ than to the resistant cultivar ‘ Baiguoqiangfeng＇. These results indicated that pre-socked seeds with Spd can alleviate salt stress injure resulting from an increase of antioxidant enzymes activities and maintenance of 1 low ROS level in the seedlings.